a. Field of the Invention
This invention relates to a rotational coupling device. In particular, the instant invention relates to a device having a variety of improvements intended to permit use of the device in applications requiring either a wet (i.e. including use of a lubricating fluid) or dry coupling device and in applications requiring either vertical or horizontal mounting arrangements.
b. Background Art
Rotational coupling devices such as clutches and brakes are used to control transfer of torque between rotational bodies. In an electromagnetic coupling device, an armature coupled to an input or output member is brought into engagement with, and/or disengagement from, a rotor coupled to the other of the input or output members in order to rotatably couple or decouple the input and output members.
Conventional electromagnetic coupling devices are often ill-suited to use in certain applications including those where a wet coupling device is desired and in applications where the device may need to be oriented vertically. For example, in devices that are oriented vertically, gravitational forces act on the armature and/or clutch plates between the armature and rotor and may cause undesirable movement and frictional engagement of these components at a time when the torque transfer is undesirable. Further, if the device is oriented vertically and a wet device is required, difficulties exist in insuring adequate lubrication of the device components in view of the gravitational forces acting on fluid in the device. It is also difficult to design a wet device in which the electromagnetic circuit provides desired operating characteristics. Use of existing devices in some environments—particularly those in which water or other liquids may be present—can also be problematic because of an inability to adequately remove such liquids and maintain the operability of the device.
The inventors herein have recognized a need for a rotational coupling device that will minimize and/or eliminate one or more of the above-identified deficiencies.